The Dimension XPS R350 was introduced well over 3.5 years ago.
Since then, this basic case, power, and mechanical design has
been an integral part of Dell''s high-end and later mid-range
product line until the Dimension 4100 was replaced by the
Dimension 4300 just a few months ago. Mechanically, the Dimension
XPS Rxxx, Txxx, Txxxr, Bxxxr, Bxxx, and 4100 are NEARLY
identical. Those of us who bought XPS R's and T's 2.5 to 3.5
years ago, were fortunate to have done so at the FRONT END of a
hardware technology cycle. This cycle began with the PII and
Intel 440BX/ZX AGP set, continuing on through the PIII, PIIIe,
ill-fated RDRAM based i820 AGP set, and finally the i815 based
machines such as the 4100. It ended with the introduction of the
i845 AGP chipset supporting the Pentium 4 systems, which took
over the mid range of Intel's (and Dell's) lineup from the PIII
based machines.

These formerly top-of-the-line Dimension XPS R/T systems
introduced Slot 1 CPUs, PC100 memory, AGP (2x) graphics, and
integrated ATA-33 IDE interfaces and had a reasonable number of
PCI slots. As a result of this, there are a number of current and
near term upgrades that can be done to increase their performance
by several fold (at least up to 3X overall). While the Coppermine
based XPS T850r benefits very little from a CPU upgrade to 1GHz,
the XPS R350 can easily gain a 3 to 1 CPU enhancement. Further,
over the next 12 months, we MAY be able to benefit from next
generation Tualatin based Celeron processors up to 1.5GHz. This
could represent nearly a 5 to 1 scaling of performance of the
basic motherboard/case over a 3-5 year life span. This is an
unheard of "good buy" in our industry.

These CPU upgrades SHOULD be easy to do. Further, memory
upgrades are inexpensive and also are straightforward. If you
have an original 1997/1998 graphics card, it almost certainly is
incapable of playing the newest games well, so video board
upgrades are probably in your future. Finally, disk I/O
performance can certainly be enhanced with the newest drives and
controller logic at very reasonable costs.

While each of these upgrades can be very cost effective, done
by itself, if you are looking to upgrade to Windows XP and are
still running Windows 98 and Office 97 in a Dimension XPS
R350-450 with 64MB to 96MB of clk=3 memory, an original really
slow/noisy 6-8GB hard drive, integrated sound, and an early AGP
video card, then the cost of purchasing all of the separate
hardware and software components may exceed the cost of
purchasing a whole new machine.

CAVEAT: These are relatively "old" machines and
most are out of warranty, so while anything CAN be done, anything
CAN also go wrong.

Key Facts: Dimension XPS Rxxx and Txxx/Txxxr

The Dell Dimension XPS Rxxx and Txxx(r) families of machines
use the similar Intel SE440BX and SE440BX-2 motherboards. They
both use the 440BX/ZX AGP set (most popular until recently in
laptops such as the Inspiron 4000 and 8000). The software support
for these from Microsoft is superb. The major functional
difference between the two machines was the change from SECC
(PII) to SECC2 (PIII) spec. in the Slot 1 CPU (largely a voltage
regulation issue introduced by the first generation Katmai PIII
processors in many of the XPS/T's) and the use of LED's instead
of beep codes for boot diagnostics. Both the SE440BX and
SE440BX-2 machines have a 100MHz front side bus (FSB), AGP 2X,
and ATA-33 IDE.

Unlike 3rd party motherboard vendors, Intel rarely allows
tweaks in their mobos. Further, Dell is usually as restrictive
(sometimes more) in what features it exposes in its own version
of the Intel BIOS. There are no clock or voltage tweaks
accessible using the Dell BIOS. The current version is A13 for
the XPS R and A11 for the XPS T. Use of Intel's BIOS (as opposed
to the DELL BIOS) for these machiones is STRONGLY discouraged.

Memory Upgrades

Both machines can be upgraded to 768MB of PC100 SDRAM, ECC or
non-ECC, CAS=2 or 3. Despite what Dell says, the SE440BX
motherboard in the XPS Rxxx can use 256MB memory sticks.

http://www.crucial.com/
is an excellent source for memory and has been shipping 2-day
Fed-ex for free. If we use fellow DelTalk member Rob Hancock's
Crucial Banner ad on his Dimension Upgrade site to enter Crucial,
we help Rob continue to keep his web site available to all of us.

Memory. prices vary, but as of early November, the price of
256MB, clk=2 PC100 memory is $27.89 (US only). For Windows
98/98SE/ME, 256MB to 512MB of clk=2 memory is recommended. For
Windows NT/2000/XP, we recommend 384MB to 768MB of clk=2 memory.
ECC is probably overkill for home use, but costs an extra
$2/stick from Crucial. These machines will default to the lowest
common denominator, so even if you spring for new clk=2, ECC
memory, if you have even one stick of old clk=3, non-ECC memory,
the whole machine runs clk=3, non-ECC.

Using an 800MHz Coppermine PIII, I have seen approximately a
10% (double word) to 15% (single word) hit in memory performance
between clk=2 and clk=3 due to higher memory latency. I use
SiSoft SANDRA or Memtach as my benchmark. If you are like many
and have 128MB of clk=3 memory and want to make the next step in
the least expensive way, then upgrading your memory to 256MB or
384MB with a single memory stick is worth more than speeding up
the memory. However, if you are going to 512MB or above, then you
will be buying at least 2 memory sticks, at which point it is
generally more cost effective to just insure you have clk=2.
Given the low prices today, more memory at the highest speed is
ALWAYS a good deal. Further, the faster your CPU (remember those
1.5GHz Celerons next year!), the more important memory speed
becomes.

You can tell if you have clk=2 or clk=3 memory by running a
CPU utility like CPU-Z from www.cpuid.com . It will tell you the
CAS/RAS settings under its Memory taskbar. Also, clk=2 PC100
memory with 1000MHz PIII should get SiSoft Sandra memory test
numbers of around 310MB/s (single word) and 340MB/s (double
word). These are reference numbers for the 440BX, clk=2. If your
mileage varies (on the down side) you almost certainly have
clk=3. On my PIII 800MHz system, clk=3 gets 260MB/s (single) and
292MB/s (double). Testing the same system with clk=2, we get
295MB/s and 333MB/s.

Processor Upgrades

The Dimension XPS R came with a 350MHz to 450MHz PII. The XPS
T came with 450MHz to 850MHz PIII. These machines are potentially
capable of running any one of up to 4 generations of Intel P6
micro-architecture with 100MHz front side bus. Today, the only
effective upgrades direct from Intel are either the 850MHz or
1000MHz slot 1 SECC2 processors. Since Intel has stopped
manufacturing these, availability will become increasingly
limited (we think!). Currently, the best price and availability
on the 1GHz part seems to be from http://www.googlegear.com
at $200.00 plus shipping.

3. Coppermine - Intel Pentium IIIe .18 uM technology - 550MHz
to 1100MHz with 256KB full speed internal 8-way cache. Celeron 2
to 1.1GHz with 128KB of 4-way cache. Available in Slot 1 (to
1GHz) or Socket 370 FC-PGA (to 1.1GHz) with slocket adapter. Most
available current upgrade. Seems to work well with all XPS R/T
(or even XPS/B but at 133MHz).

4. Tualatin - Intel Pentium IIIt - Speeds to 1.26GHz with up
to 512KB full speed cache (PIII-Server/Mobile) - 133MHz FSB ONLY!
Regular desktop PIII-T goes to 1.2GHz and has 256KB cache and
133MHz FSB. Celeron-T to 1.2GHz with 256KB one wait state 8-way
cache and data pre-fetch with 100MHz FSB. New pin out and power
requirements force changes to all PIII infrastructure. No Slot 1
format. Requires Powerleap PL-iP3/T (see: http://www.powerleap.com/Products/iP3T.htm).
All models have data pre-fetch and deeper memory buffers for more
efficient memory utilization. Intel will continue to upgrade the
Celeron (for value market) and PIII-M (for mobile) market through
most of 2002.

Since all Tualatin PIII processors run with a 133MHz FSB, we
need to look into the Celeron family for upgrades past the 1.1GHz
mark as we move into the future.

The Good:

1. The Tualatin Celeron has an 8-way set associative cache and
data pre-fetch, so is slightly better performance per clock-cycle
than the Coppermine PIII. Given that the cache is 256KB, it
equals the Coppermine PIII and is MUCH better than the Coppermine
Celeron.

2. Rob Hancock tested the Powerleap PL-iP3/T. Its performance
substantially exceeds that of the 1GHz Coppermine PIII in my
personal XPS R. See: http://www.roberthancock.com/dell/plip3t/
. At $170.00 list price, it is less expensive than the
increasingly unavailable $210 1GHz retail Coppermine Intel part.
My comparisons of 1GHz performance vs. 1.2GHz performance are
based on running EXACTLY the same tests that Rob Hancock ran
using my own 1GHz PIII Coppermine XPS R. Like Rob, I ran SiSoft
SANDRA 2001te, but I have clk=2 memory instead of clk=3. This
software is available as de-featured freeware from http://www.sisoft.com.

Please notice that the ratio between the two is between 1.21
to 1.26 to 1. This means that the Tualatin is actually slightly
better than the Coppermine on a clock for clock basis. If Rob had
clk=2 SDRAM, I would expect memory bandwidth numbers similar or
just slightly better. SANDRA's CPU benchmarks seem nearly the
same whether you have PC100 or PC133 memory (on the Coppermine
PII), so I doubt that the CPU numbers would be dramatically
different (maybe the FPU numbers might since they are double word
memory references instead of single word).

3. Current information from Intel for the Tualatin Celeron-T
shows the following roadmap - which is very much subject to
change!:

In general computing benchmarks, a PIII 1GHz processor is
roughly equivalent to 1.3GHz or 1.4GHz P4. Assuming linear
scaling, by mid-late 2002, we could have a 1.5GHz Celeron-T that
would be in the same raw performance class as the current
Dimension 4300 with 1.6-1.8 GHz P4 and PC133 SDRAM.

4. If you expect to continue to run the same O/S (Windows
9x/ME NT/2000) and applications for at least another year, there
are a number of very cost effective upgrades that can extend the
life of your machine that require NO software work (or very
little) and provide very substantial performance improvements.

The Bad:

1. At 100MHz, the FSB of the XPS R/T family has a bandwidth
limit of 800MB/s. The useable bandwidth of this bus (using
Memtach) is no more than around 500MB/s. Current P4 RDRAM
machines benchmark as high as 1.7GB/s. With modern ATA-100
drives, high-end graphics processors, and much faster CPU's,
these machines can easily become memory bound. It has already
been seen that 1.06GB/s PC133 memory is a significant bottleneck
on the mid-range 845-based P4's and can cause as much as a 30%
application performance hit over identical RDRAM machines.

2. The Powerleap slocket adapter is not yet shipping in volume
nor is there a lot of experience with it in the market.

3. Past 1GHz, we appear to be dependent on a single small
vendor to provide the form factor, voltage, and signaling
adaptation required to use the Tualatin processors in our now 3
generation-old motherboards. Given the vagaries of today's
technology market, one must ask whether Powerleap will survive
the current tech-depression? Answer unknown.

4. While the PIII Tualatin with 512KB cache used in the PIII-M
and PIII-S almost (but not quite) matches the AMD Athlon family
on a clock for clock basis, it requires a 133MHz FSB. The smaller
Celeron cache and 100MHz FSB will become bigger factors as the
core CPU clock rate increases.

The Ugly:

1. If you are upgrading to Windows XP, you MAY have a lot of
work to do to. You need to round up the latest and greatest
drivers for all of your random hardware. Since Dell is not
providing Windows XP support for the XPS R/T, you will NOT be
getting these drivers from Dell, but instead from the OEM's who
produce the equipment in your Dell or from the support provided
by Microsoft's on its installation CD. In any case, YOU are
responsible for the system integration of your components into
Windows XP, not Dell.

2. You may have to upgrade applications. You WILL end up
having to re-install Outlook 97/2000/2002 due to differences
between Win 9x and Win 2000/XP implementation. If you have
religiously installed all patches like I have, this means
re-installing all of Office, not just Outlook. This re-install
looks like a NEW install due to Windows XP and will require a
call to Microsoft to get "relicensed". If you install
all of security and functionality patches for Office 2000 that I
do, the process takes hours.

3. A new Dell computer will come with Windows XP already
integrated to the hardware configuration you purchase. It will
also come with Office XP (SBE or Pro) for a surcharge of
$150-$350 over a basic Works install. These prices are roughly
equivalent to (or better than) installing a retail Office XP
upgrade from CompUSA. Plus you get a new Norton Anti-virus, Image
Expert, WinDVD (for the DVD drive) and other free software from
Dell that may require costly upgrades for Windows XP.

4. Currently, the Dell 4300 is limited by its 1.06GB/s of
PC133 memory bandwidth. This is especially so because the P4 is
more "memory intensive" than the PIII. By early next
year, Intel should be supporting DDR 845 chipsets (Double Data
Rate) for Dimension 4300 class machines. This will allow 2.1 GB/s
(133Mx2) to 2.7 GB/s (166Mx2) of low-latency memory to the
bandwidth hungry P4. Further, the P4 will have been moved to a
.13 uM process. This is expected to reduce power consumption,
increase the cache size to 512KB, and support MUCH higher clock
rates (easily to 2.5GHz+). Within 3 to 6 mos., 6 to 9 at most, I
can easily envision a Dimension 4300-class machine ($1300-$1800)
at 2.0GHz+ with equal or more raw performance than today's
highest end Dimension 8200 ($2200-$2500).

SUMMARY: I think that up to $200 spent on a CPU upgrade
for the Dimension XPS R/T machines, GIVEN that the rest of the
machine is in good condition and has reasonably current HDD's,
memory, and video, is a good investment.